Tuesday, January 25, 2011

The History of Computing II - The IBM PC

For decades after World War II, computers were shared. Though they had grown smaller since the days of ENIAC, they were still very large and expensive. As a consequence, entire universities or companies, or even groups of schools and companies, would share the use of a single, large, and—for the time—powerful computer.

The people who used this mainframe, as these computers were called, would often never see it. The computer was generally locked in a secure location, and users would connect to it through phone lines or other wiring. At first, all the user saw was a teletype, which is like a combination of an electric typewriter and a printer. But later, video screens were introduced, which showed green or orange text on a black background.

By the late 1970s, computer scientists realized that smaller, less powerful computers could be placed right on user’s desks. “Garage” companies, so named because they were so small they might literally consist of one or two people working out of a garage, began making small computers for individuals, not whole companies. Sometimes these computers came in the form of kits.

IBM, the company that grew out of Hollerith’s census tabulators, was at this time very successful making mainframes. At first, IBM was skeptical that a market even existed for smaller computers, but eventually it decided to act. In 1981 the company introduced the IBM PC. The “PC” stood for “personal computer,” which is where that term for a single-user computer originates.

The price was over $1,500, which in 1980 was a lot of money, but it was still remarkably inexpensive compared to mainframes. In addition, the IBM name gave the personal computer instant legitimacy. Yet, the IBM PC did not mark a revolution in technology. The machine had been built almost entirely from off-the-shelf parts. What was revolutionary was the concept: A computer would appear on our desks at work, would come into our homes, would become an ordinary appliance like the telephone. At the start of 1983, when Time magazine would normally select its “Man of the Year,” for 1982, the editors instead selected “The Computer” as its “Machine of the Year.” The computer had come of age.

As you will find, today’s computers are not simply a little faster than the original desktops. A gymnasium full of IBM PCs would not equal the power of a single system today. You may not know what all these terms mean, but you will before you finish this book. For now, just marvel at how little $1,500 once bought (or, to be optimistic, how much $1,500 buys now).

Source of Information : Broadway-Computer Science Made Simple 2010
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